U.S. patent number 6,890,630 [Application Number 10/029,375] was granted by the patent office on 2005-05-10 for elastic composites for garments.
This patent grant is currently assigned to Kimberly-Clark Worldwide, Inc.. Invention is credited to Valerie V. Finch, Kent A. Franklin, Robin K. Nason, Jon M. Verbruggen.
United States Patent |
6,890,630 |
Franklin , et al. |
May 10, 2005 |
Elastic composites for garments
Abstract
An elastic composite is formed by securing an elastic member to
a substrate along a securement path extending longitudinally of the
substrate. The position of the elastic member on the substrate
varies laterally along the longitudinally extending securement path
in a generally periodic wave pattern having at least one period
within the securement path. The periodic wave pattern is such that
the elastic composite is more stretchable in the direction of the
securement path than transverse to the securement path. In another
embodiment, the securement path varies laterally as it extends
longitudinally along the securement path. The position of the
elastic member varies transversely within the securement path to at
least partially define a width of the securement path.
Inventors: |
Franklin; Kent A. (Appleton,
WI), Finch; Valerie V. (Neenah, WI), Nason; Robin K.
(Oshkosh, WI), Verbruggen; Jon M. (Little Chute, WI) |
Assignee: |
Kimberly-Clark Worldwide, Inc.
(Neenah, WI)
|
Family
ID: |
21848688 |
Appl.
No.: |
10/029,375 |
Filed: |
December 20, 2001 |
Current U.S.
Class: |
428/212; 428/138;
428/152; 428/198; 428/213; 428/220 |
Current CPC
Class: |
A61F
13/15593 (20130101); A61F 13/15609 (20130101); A61F
13/49017 (20130101); A61F 13/4942 (20130101); A61F
13/5148 (20130101); Y10T 442/3024 (20150401); Y10T
442/602 (20150401); Y10T 442/681 (20150401); Y10T
442/601 (20150401); Y10T 442/674 (20150401); Y10T
428/24091 (20150115); Y10T 428/24107 (20150115); Y10T
428/2495 (20150115); Y10T 428/24446 (20150115); Y10T
428/24331 (20150115); Y10T 428/24942 (20150115); Y10T
428/24322 (20150115); Y10T 428/24083 (20150115); Y10T
428/24826 (20150115) |
Current International
Class: |
A61F
13/15 (20060101); B32B 007/02 () |
Field of
Search: |
;428/213,220,138,198,152,212 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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Other References
Partial International Search PCT/US 02/20722, dated Dec. 17, 2003,
2 pages. .
International Search Report for PCT/US 02/41454 dated Jul. 17, 2003
(6 pages). .
International Search Report for PCT/US 02/20723 dated Dec. 20, 2001
(5 pages)..
|
Primary Examiner: Dixon; Merrick
Attorney, Agent or Firm: Senniger Powers
Claims
What is claimed is:
1. An elastic composite comprising a substrate and first and second
elastic members secured to the substrate along a securement path
extending longitudinally along the substrate, said first elastic
member being secured to the substrate so that the position of said
first elastic member on the substrate varies transversely within
said securement path in a first generally periodic wave pattern
having at least one period within said securement path, said second
elastic member being secured to said substrate so that the position
of said second elastic member varies transversely within said
securement path in a second generally periodic wave pattern having
at least one period within said securement path, said first and
second generally periodic wave patterns being shaped such that the
elastic composite is more stretchable in the direction of the
securement path than in the direction transverse to the securement
path.
2. An elastic composite as set forth in claim 1 wherein the
periodic wave pattern of at leas one of said first and second
elastic members has a slope of between about -1 and 1 relative to
the direction of the securement path.
3. An elastic composite as set forth in claim 2 wherein the
periodic wave pattern of at least one of said first and second
elastic members is generally sinusoidal.
4. An elastic composite as set forth in claim 1 wherein said first
and second elastic members are coextensive along the securement
path.
5. An elastic composite as set forth in claim 1 wherein said first
and second elastic members are secured to the substrate in
generally parallel, spaced relationship with each other along at
least a portion of the securement path.
6. An elastic composite as set forth in claim 1 wherein said first
and second elastic members are secured to the substrate in
generally transversely spaced relationship with each other along at
least a portion of the securement path, the transverse spacing
between said first and second elastic members varying along said
portion of the securement path.
7. An elastic composite as set forth in claim 1 wherein said first
and second elastic members cross each other at least once within
the securement path.
8. An elastic composite as set forth in claim 1 wherein the
periodic wave pattern of the second elastic member is substantially
the same as the periodic wave pattern of the first elastic
member.
9. An elastic composite as set forth in claim 1 wherein the
periodic wave pattern of the second elastic member is substantially
the negative of the periodic wave pattern of the first elastic
member.
10. An elastic composite as set forth in claim 9 wherein the first
and second elastic members cross each other at least once within
the securement path.
11. An elastic composite comprising a substrate and an elastic
member secured to the substrate along a securement path extending
longitudinally along the substrate, the securement path varying
laterally relative to the substrate as it extends longitudinally
along the substrate, the position of the elastic member varying
transversely within the securement path to at least partially
define a width of the securement path.
12. An elastic composite as set forth in claim 11 wherein the
elastic member is secured to the substrate in a generally periodic
wave pattern having at least one period within the securement
path.
13. An elastic composite as set forth in claim 12 wherein the
periodic wave pattern of the elastic member is shaped such that the
elastic member has a slope of between about -1 and 1 relative to
the direction of the securement path.
14. An elastic composite as set forth in claim 12 wherein the
periodic wave pattern of the elastic member is generally
sinusoidal.
15. An elastic composite as set forth in claim 11 wherein the
elastic member is a first elastic member, said composite further
comprising a second elastic member secured to the substrate; said
first and second elastic members together at least partially
defining said securement path width, the position of the second
elastic member varying transversely within the securement path.
16. An elastic composite as set forth in claim 15 wherein said
first and second elastic members are coextensive along the
securement path.
17. An elastic composite as set forth in claim 15 wherein said
first and second elastic members are secured to the substrate in
generally parallel, spaced relationship with each other along at
least a portion of the securement path.
18. An elastic composite as set forth in claim 15 wherein said
first and second elastic members are secured to the substrate in
generally transversely spaced relationship with each other along at
least a portion of the securement path, the transverse spacing
between said first and second elastic members varying along said
portion of the securement path.
19. An elastic composite as set forth in claim 15 wherein said
first and second elastic members cross each other at least once
within the securement path.
20. An elastic composite as set forth in claim 15 wherein the
periodic wave pattern of the second elastic member is substantially
the same as the periodic wave pattern of the first elastic
member.
21. An elastic composite as set forth in claim 15 wherein the
periodic wave pattern of the second elastic member is substantially
the negative of the periodic wave pattern of the first elastic
member.
22. A elastic composite as set forth in claim 21 wherein the first
and second elastic members cross each other at least once within
the securement path.
23. An elastic composite comprising a substrate and an elastic
member secured to the substrate along a crooked securement path,
the position of the elastic member varying transversely within the
securement path to at least partially define a width of the
securement path.
24. An elastic composite as set forth in claim 23 wherein the
securement path defines a periodic pattern, at least one period of
which is formed on the substrate, the position of the elastic
member varying transversely within the securement path in a
generally periodic pattern having at least two periods within each
period of the pattern defined by the securement path.
25. An elastic composite as set forth in claim 23 wherein the
securement path is arcuate.
26. An elastic composite as set forth in claim 25 wherein the
elastic member is secured to the substrate along the securement
path such that the composite is more stretchable in the direction
of the securement path than transverse to the securement path.
Description
BACKGROUND OF THE INVENTION
The present invention relates to garments having elastic components
therein, and more particularly to elastic composites formed within
such garments, or formed separately from such garments and secured
therein, to provide an elastic component to such garments.
Garments such as conventional clothing items as well as disposable
absorbent articles often have elastic composites formed or
incorporated therein which permit stretching and provide retractive
forces to certain portions of the garment to provide a snug but
comfortable fit for the wearer. Elastic composites also allow the
garment to fit a greater range of wearer sizes. To form the elastic
composite, one or more elastic members, such as strands of elastic
material, are typically secured to a substrate, such as a layer of
the garment material, while in a stretched condition to thereafter
apply is a retractive force to the substrate for gathering the
substrate. The elastic composite may also be formed by securing one
or more elastic members to a substrate separate from the garment,
such as in the form of a strip, or ribbon. The elastic composite is
then secured to the garment to incorporate the elastic composite
therein.
Children's toilet training pants are one example of a garment which
may incorporate elastic composites. Training pants, which serve as
a disposable training aid as a child transitions from diapers to
underpants, are three-dimensional articles similar to underpants in
appearance but constructed with a liquid permeable inner layer and
an absorbent body to provide the absorbent function of a disposable
absorbent article. Elastic members in the form of elastic strands
are secured within the toilet training pants at the leg openings
and sometimes in other areas of the training pants such as the
waist opening and, if present, along containment flaps of the
pants. The strands are adhered to a layer, or more typically
between two layers, of the training pants, such as along the sides
of the training pants adjacent the leg openings. The strands are
secured within pants while in a stretched condition (e.g., in
tension) so that the retractive force of the strands gathers the
pants at the leg openings to provide a snug fit around the wearer's
legs.
However, despite the benefits of forming or incorporating elastic
composites into garments, there continues to be a need for
improvements in the formation of such elastic composites. For
example, there continues to be a need for increasing the comfort of
such garments against the wearer's skin and for making a more
efficient use of elastic members in disposable absorbent articles
to thereby decrease the cost of manufacturing such articles.
SUMMARY OF THE INVENTION
In general, an elastic composite of the present invention comprises
a substrate and an elastic member secured to the substrate along a
securement path extending longitudinally along the substrate. The
position of the elastic member on the substrate varies transversely
within the securement path in a generally periodic wave pattern
having at least one period within the securement path. The periodic
wave pattern is shaped such that the elastic composite is more
stretchable in the direction of the securement path than transverse
to the securement path.
In another embodiment, the elastic composite comprises a substrate
and an elastic member secured to the substrate along a securement
path extending longitudinally along the substrate. The securement
path varies laterally relative to the substrate as it extends
longitudinally along the substrate. The position of the elastic
member varies transversely within the securement path to at least
partially define a width of the securement path.
In yet another embodiment, the elastic composite comprises a
substrate and an elastic member secured to the substrate along a
crooked securement path. The position of the elastic member varies
transversely within the securement path to at least partially
define a width of the securement path.
In still another embodiment, the elastic composite comprises a
substrate and a pair of elastic members secured to the substrate in
generally transversely spaced relationship with each other along a
crooked securement path. The transverse spacing between the elastic
members defines a width of the securement path. The securement path
width varies along its length.
In general, a disposable absorbent article of the present invention
comprises a liner adapted for contiguous relation with the wearer's
skin, an outer cover, and an absorbent body between the liner and
the outer cover for absorbing liquid body waste. At least one
elastic member is secured within the article along a generally
crooked securement path. The position of the at least one elastic
member varies transversely within the securement path to at least
partially define a width of the securement path.
In another embodiment, the absorbent article comprises a liner
adapted for contiguous relation with the wearer's skin, an outer
cover, and an absorbent body between the liner and the outer cover
for absorbing liquid body waste. At least one elastic member is
secured within the article along a securement path. The position of
the at least one elastic member varies transversely within the
securement path in a generally periodic wave pattern having at
least one period within the securement path. The periodic wave
pattern is shaped such that said article is more stretchable in the
direction of the securement path than transverse to the securement
path.
In general, a method of the present invention for forming an
elastic composite comprises moving a substrate in a flow direction
thereof, guiding an elongate elastic member onto the substrate and
securing the elastic member to the substrate. The guiding step
comprises varying the lateral position of the elastic member
relative to the flow direction of the substrate to vary the
position of the elastic member transversely within the securement
path in a generally periodic wave pattern. The periodic wave
pattern is shaped such that the formed elastic composite is more
stretchable in the direction of the securement path than transverse
to the securement path.
In another embodiment, the method comprises moving a substrate in a
flow direction thereof and guiding an elongate elastic member onto
the substrate along a securement path. At least a portion of the
securement path is oblique relative to the flow direction of the
substrate. The guiding step comprises varying the lateral position
of the elastic member relative to the flow direction of the
substrate to vary the position of the elastic member transversely
within the securement path. The elastic member is then secured to
the substrate.
Other aspects and features of this invention will be in part
apparent and in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side perspective of a children's toilet training
pants;
FIG. 2 is a top plan view of the training pants of FIG. 1 with the
pants shown unfastened and laid flat and portions of the pants
broken away to reveal an elastic composite of the present
invention;
FIG. 2A is an enlarged view of a portion of the training pants of
FIG. 2;
FIG. 3 is a separated cross-section of the training pants of FIG. 1
taken laterally through a crotch region of the pants;
FIGS. 4A, 4B and 4C are schematics of various patterns that may be
defined by elastic members of the elastic composite of the present
invention;
FIG. 5 is a top plan view of training pants similar to FIG. 2
illustrating a pattern that may be defined by leg elastic members
of the training pants;
FIG. 6 is a diagrammatic top plan view of apparatus of the present
invention for guiding one or more elastic members onto a substrate
to form an elastic composite of the present invention;
FIG. 7 is a front view thereof;
FIG. 8 is a side view thereof;
FIG. 9 is a top plan view of the apparatus of FIG. 6 with guides of
the apparatus moved transversely outward relative to each
other;
FIG. 10 is a front view thereof;
FIG. 11 is a top plan view of the apparatus of FIG. 6 with a guide
assembly of the apparatus moved transverse to a drive assembly of
the apparatus;
FIG. 12 is a schematic side view of a system of the present
invention for applying a plurality of elastic members to children's
toilet training pants; and
FIG. 13 is a schematic top plan view thereof.
Corresponding reference characters indicate corresponding parts
throughout the drawings.
Definitions
Within the context of this specification, each term or phrase below
will include the following meaning or meanings:
(a) "Bonded" refers to the joining, adhering, connecting,
attaching, or the like, of two elements. Two elements will be
considered to be bonded together when they are bonded directly to
one another or indirectly to one another, such as when each is
directly bonded to intermediate elements.
(b) "Film" refers to a thermoplastic film made using a film
extrusion and/or foaming process, such as a cast film or blown film
extrusion process. The term includes apertured films, slit films,
and other porous films which constitute liquid transfer films, as
well as films which do not transfer liquid.
(c) "Hydrophilic" describes fibers or the surfaces of fibers which
are wetted by aqueous liquids in contact with the fibers. The
degree of wetting of the materials can, in turn, be described in
terms of the contact angles and the surface tensions of the liquids
and materials involved. Equipment and techniques suitable for
measuring the wettability of particular fiber materials or blends
of fiber materials can be provided by a Cahn SFA-222 Surface Force
Analyzer System, or a substantially equivalent system. When
measured with this system, fibers having contact angles less than
90 degrees are designated "wettable" or hydrophilic, and fibers
having contact angles greater than 90 degrees are designated
"nonwettable" or hydrophobic.
(d) "Layer" when used in the singular can have the dual meaning of
a single element or a plurality of elements.
(e) "Liquid impermeable," when used in describing a layer or
multi-layer laminate means that liquid body waste, such as urine,
will not pass through the layer or laminate, under ordinary use
conditions, in a direction generally perpendicular to the plane of
the layer or laminate at the point of liquid contact.
(f) "Liquid permeable" refers to any material that is not liquid
impermeable.
(g) "Meltblown" refers to fibers formed by extruding a molten
thermoplastic material through a plurality of fine, usually
circular, die capillaries as molten threads or filaments into
converging high velocity heated gas (e.g., air) streams which
attenuate the filaments of molten thermoplastic material to reduce
their diameters. Thereafter, the meltblown fibers are carried by
the high velocity gas stream and are deposited on a collecting
surface to form a web of randomly dispersed meltblown fibers. Such
a process is disclosed, for example, in U.S. Pat. No. 3,849,241 to
Butin et al. Meltblown fibers are microfibers which may be
continuous or discontinuous, are generally smaller than about 0.6
denier, and are generally self bonding when deposited onto a
collecting surface. Meltblown fibers used in the present invention
are preferably substantially continuous in length.
(h) "Non-woven" and "non-woven web" refer to materials and webs of
material which are formed without the aid of a textile weaving or
knitting process.
(i) "Pliable" refers to materials which are compliant and which
will readily conform to the general shape and contours of the
wearer's body.
(j) "Spunbond" refers to small diameter fibers which are formed by
extruding molten thermoplastic material as filaments from a
plurality of fine capillaries of a spinnerette having a circular or
other configuration, with the diameter of the extruded filaments
then being rapidly reduced by a conventional process such as that
described in U.S. Pat. No. 4,340,563 to Appel et al., U.S. Pat. No.
3,692,618 to Dorschner et al., U.S. Pat. No. 3,802,817 to Matsuki
et al., U.S. Pat. Nos. 3,338,992 and 3,341,394 to Kinney, U.S. Pat.
No. 3,502,763 to Hartmann, U.S. Pat. No. 3,502,538 to Peterson, and
U.S. Pat. No. 3,542,615 to Dobo et al., each of which is
incorporated herein in its entirety by reference. Spunbond fibers
are generally continuous and often have average deniers larger than
about 0.3, more particularly, between about 0.6 and about 10.
(k) "Superabsorbent" refers to a water-swellable, water-insoluble
organic or inorganic material capable, under the most favorable
conditions, of absorbing at least about 15 times its weight and,
more desirably, at least about 30 times its weight in an aqueous
solution containing 0.9 weight percent sodium chloride. The
superabsorbent materials can be natural, synthetic and modified
natural polymers and materials. In addition, the superabsorbent
materials can be inorganic materials, such as silica gels, or
organic compounds such as cross-linked polymers.
(l) "Thermoplastic" describes a material which softens when exposed
to heat and which substantially returns to a non-softened condition
when cooled to room temperature.
(m) "Three dimensional" refers to a garment similar to underwear,
shorts or pants in that it has continuous leg and waist openings
that are bounded by material of which the garment is made. The
garment may or may not have manually tearable seams.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and in particular to FIG. 1, an
elastic composite constructed in accordance with the present
invention is shown and described herein with reference to a
disposable absorbent article, and more particularly to a pair of
children's toilet training pants, which is indicated in its
entirety by the reference numeral 21. As used herein, a disposable
absorbent article refers to an article which may be placed against
or in proximity to the body (i.e., contiguous to the body) of the
wearer to absorb and contain various liquid waste discharged from
the body. Such articles are intended to be discarded after a
limited period of use instead of being laundered or otherwise
restored for reuse.
By way of illustration only, various materials and methods for
constructing training pants 21 are disclosed in PCT Patent
Application WO 00/37009 published Jun. 29, 2000 by A. Fletcher et
al; U.S. Pat. No. 4,940,464 issued Jul. 10, 1990 to Van Gompel et
al.; and U.S. Pat. No. 5,766,389 issued Jun. 16, 1998 to Brandon et
al., which are incorporated herein by reference.
The training pants 21 of the illustrated embodiment have a
longitudinal axis X and a lateral axis Y as indicated in FIG. 2 and
generally comprise a central absorbent assembly 23 extending
longitudinally from an anterior region 25 of the training pants
through a crotch region 27 to a posterior region 29 of the training
pants. The central absorbent assembly 23 is generally rectangular,
and more particularly it is hourglass shaped, and has laterally
opposite side edges 31 and longitudinally opposite front and rear
waist edges or ends, respectively designated 33 and 35. As best
seen in FIG. 2, the side edges 31 of the training pants 21 extend
longitudinally from the anterior region through the crotch region
to the posterior region for forming transversely spaced leg
openings 47 (FIG. 1) of the training pants 21. Front and rear side
panels 37, 39, respectively, are secured to the central absorbent
assembly 23 as will be described later herein and extend laterally
outward therefrom respectively at the anterior and posterior
regions 25, 29 of the training pants 21.
To form the three-dimensional training pants 21, corresponding
front and rear side panels 37, 39 (e.g., the front left side panel
and the rear left side panel) are refastenably secured together,
using fastening assemblies 41, along generally vertical seams 43.
Alternatively, the front and rear side panels 37, 39 may be
permanently secured together, such as by ultrasonic bonding, or
they may be formed integrally with each other and/or with the
central absorbent assembly 23. Securing the side panels 37, 39
together provides a central waist opening 45 and the transversely
spaced leg openings 47 of the training pants 21. The training pants
21 are worn by inserting the wearer's feet through the waist
opening 45 and the respective leg openings 47; grasping the
training pants near the waist opening; and then pulling the pants
up along the wearer's legs until the crotch region 27 of the
training pants fits snugly against the crotch of the wearer.
With reference to FIG. 3, the central absorbent assembly 23 of the
training pants 21 comprises an outer cover, generally indicated at
49, a bodyside liner 51 and an absorbent body 53 disposed between
the outer cover and the liner. The outer cover 49 can be elastic,
stretchable or non-stretchable and is desirably a multi-layered
laminate structure of which at least one of the layers is liquid
impermeable. For example, the outer cover 49 of the illustrated
embodiment is of two-layer construction, including an outer layer
55 constructed of a liquid permeable material and an inner layer 57
constructed of a liquid impermeable material joined together by a
laminate adhesive 59. It is understood that the outer cover 49 may
instead be constructed of a single layer of impermeable material
without departing from the scope of this invention.
The liquid permeable outer layer 55 of the outer cover 49 can be
any suitable material and is desirably one which provides a
generally cloth-like texture. One example of such a material is a
20 gsm (grams per square meter) spunbond polypropylene non-woven
web. The outer layer 55 may also be constructed of the same
materials from which the bodyside liner 51 is constructed as
described later herein. Also, while it is not a necessity for the
outer layer 55 of the outer cover 49 to be liquid permeable, it is
desired that it provide a relatively cloth-like texture to the
wearer.
The liquid impermeable inner layer 57 of the outer cover 49 can be
either vapor permeable (i.e., "breathable") or vapor impermeable.
The inner layer 57 is desirably manufactured from a thin plastic
film, although other flexible liquid impermeable materials may also
be used. The liquid impermeable inner layer 57 (or the liquid
impermeable outer cover 49 where the outer cover is of a
single-layer construction) inhibits liquid body waste from leaking
out of the pants and wetting articles, such as bed sheets and
clothing, as well as the wearer and care giver.
Leg elastic members 61 are secured between the outer and inner
layers 55, 57 of the outer cover 49, such as by being bonded to one
or both layers by the laminate adhesive 59. Thus it will be seen
that the outer and inner layers 55, 57 of the outer cover 49 each
broadly define a substrate to which the elastic members 61 may be
secured to broadly form an elastic composite of the present
invention. It understood that the leg elastic members 61 may be
secured between the outer and inner layers 55, 57 of the outer
cover 49 by adhesive (not shown) other than the laminate adhesive.
It is also understood that the leg elastic members 61 may instead
be secured between the outer cover 49 and the bodyside liner 51. In
such a design, the leg elastic members 61 can be bonded to the
outer cover 49, to the bodyside liner 51, or to both.
The elastic members 61 are desirably strands or threads of elastic
material. However, as is well known to those skilled in the art,
suitable elongate elastic members 61 also include sheets, ribbons
of natural rubber, synthetic rubber, or thermoplastic elastomeric
polymers. For example, one suitable elastic material from which the
elastic members 61 may be constructed is a dry-spun coalesced
multifilament elastomeric thread sold under the trade name
LYCRA.RTM. and available from E.I. du Pont de Nemours and Company,
Wilmington, Del., U.S.A. The leg elastic members 61 are desirably
secured between the outer and inner layers 55, 57 of the outer
cover 49 while in a stretched (e.g., elastically contractible)
condition such that retractive forces of the elastic members gather
the training pants at the leg openings 47 to provide a snug fit
around the wearer's legs. The elastic members 61 may also be
colored to provide an aesthetic appearance to the pants 21.
With reference to FIGS. 2 and 2A, the elastic members 61 are
secured within the training pants 21 along respective securement
paths, generally indicated at 63, extending longitudinally adjacent
the laterally opposite side edges 31 of the training pants 21. The
position of each elastic member 61 varies transversely within the
respective securement path 63. As used herein, the term securement
path 63 refers to the path along which one or more elastic members
61 are adhered to a substrate. As seen best in FIG. 2A, the
securement path 63 has a width W defined by edge boundaries A, B of
the elastic members 61. For example, one edge boundary A passes
generally through the maxima of one outermost elastic member and
the other edge boundary B passes generally through the minima of
the opposite outermost elastic member. A centerline C of the
securement path 63 extends midway between the edge boundaries A, B
of the securement path. Where the positions of the elastic members
61 do not vary transversely relative to the securement path, such
as in conventional training pants, the edge boundaries A, B are
substantially co-linear with the outermost elastic members.
Where only one elastic member 61 is applied to a substrate (e.g.,
as shown in FIG. 4C), one edge boundary A passes generally through
the maxima defined by the transverse position of the elastic member
relative to the securement path 63 and the other edge boundary B
passes generally through the minima defined by the transverse
position of the elastic member relative to the securement path.
Where the position of the elastic member does not vary transversely
relative to the securement path, the width W defined by a single
elastic member would be substantially zero and the centerline C and
edge boundaries A, B of the securement path would all be
co-linear.
The securement path 63 of the illustrated embodiment of FIG. 2 is
broadly referred to herein as being crooked in that it varies
laterally as it extends longitudinally adjacent the side edges 31
of the training pants 21 generally oblique, or non-parallel to the
longitudinal axis X of the training pants. For example, the
securement path 63 desirably follows the contour of the side edges
31 of the training pants 21, such as in a curvilinear or arcuate
path, although it is understood that the securement path 63 may not
follow the contour of the side edges, and may even extend in
parallel relation to the longitudinal axis of the pants 21. As used
herein, the securement path 63 is also considered to be crooked if
the centerline C and/or either one of the edge boundaries A, B of a
portion of the securement path 63 is arcuate, bent or otherwise
oblique relative to a particular axis, such as the longitudinal
axis of the pants 21. Each leg elastic member 61 shown in FIG. 2
defines a generally periodic pattern, and more particularly a
periodic wave pattern such as a sinusoidal pattern, along at least
a portion of the securement path 63 of the elastic members.
Desirably, at least two periods of the pattern are formed along the
length of the securement path, e.g., within the training pants
21.
FIGS. 2, 4A, 4B, 4C and 5 are illustrative of a few patterns which
can be defined by the elastic members 61 as they extend within the
securement path 63. For example, FIG. 4A illustrates a pair of
elastic members 61 defining two periodic wave patterns, each
generally having an amplitude A and a period T, within the width W
of the securement path 63. Preferably, at least one period T of the
periodic wave pattern of each elastic member 61 is formed as the
elastic member extends along the length of the securement path 63.
The amplitude A and period T of the periodic wave pattern formed by
each elastic member 61 are desirably formed such that the substrate
to which the elastic member is bonded, e.g., the outer and inner
layers 55, 57 of the outer cover 49, is more stretchable in the
direction of the securement path 63 (e.g, generally tangential to
the securement path) than in a generally transverse direction
relative to the securement path. For example, a slope S defined by
the change in the transverse position of each elastic member 61
within the securement path 63 as it extends in the direction of the
securement path is desirably between about -1 and about 1. However,
it is contemplated that the slope S may be greater than 1, or less
than -1, and/or that the substrate to which the elastic member is
secured is as stretchable, or more stretchable, in the transverse
direction relative to the securement path 63 without departing from
the scope of this invention.
The elastic members 61 shown in FIG. 4A generally have a constant
and equal amplitude A and period T, with the periodic wave pattern
of one elastic member being the negative of the other (e.g.,
180.degree. out of phase therewith) so that the transverse spacing
between the elastic members varies within the securement path 63.
The elastic members 61 are also sufficiently spaced so that they do
not cross each other within the securement path 63. As in FIG. 4A,
the periodic wave patterns of the elastic members 61 shown in FIG.
2 also have a substantially constant and equal amplitude and period
throughout the securement path 63, and the periodic wave pattern
defined by one elastic member is the negative of the periodic wave
pattern defined by the other elastic member. The elastic members 61
of FIG. 2 are sufficiently close so that the elastic members
periodically cross each other along the securement path 63.
FIG. 4B illustrates two pairs of elastic members 61 extending along
the securement path 63. In this embodiment, each pair of elastic
members 61 defines two periodic wave patterns having a
substantially constant and equal amplitude and period, with the
elastic members arranged in parallel, spaced relationship with each
other along the securement path 63. The periodic wave patterns of
one pair of elastic members 61 are the negative of the periodic
wave patterns of the other pair of elastic members. FIG. 4C
illustrates a single elastic member 61 defining the securement path
63.
FIG. 5 illustrates training pants 21 having a pair of elastic
members 61 similar to those shown in FIG. 2 extending along each of
the securement paths 63 formed adjacent the leg openings 47 of the
training pants 21. Along a segment of the securement path 63, the
elastic members 61 extend along arcs having different radii such
that the elastic members are spaced transversely from each other in
non-parallel relationship, thereby varying the width W of the
securement path.
It is contemplated that the pattern of one elastic member 61 may
have a different amplitude and/or period than the pattern of the
other elastic member, and the elastic members may be more closely
or distantly spaced relative to each other than as shown in the
illustrated embodiments, without departing from the scope of this
invention. It is also understood that one elastic member 61 may not
extend the full length of the securement path 63, or that only a
single elastic member may extend along the securement path.
By securing the leg elastic members 61 between the outer and inner
layers 55, 57 of the outer cover 49 in a generally periodic wave
pattern within the securement path 63, the elastic members affect a
substantially increased surface area of the outer cover in
comparison to elastic members secured generally parallel to or
otherwise co-linear with the securement path. As a result, the
retractive forces of the elastic members 61 act against a greater
surface area of the wearer's skin (i.e., a surface area roughly
equal to the width of the securement path times its length),
thereby increasing comfort to the wearer and reducing the risk that
the elastic members will leave indentations or marks on the wearer.
Also, because the elastic members 61 are spread over a wider
surface area of the outer cover 49, a lesser number of elastic
members may be needed to provide the desired fit of the pants 21
against the wearer's skin. For example, a pair of elastic members
61 formed in periodic wave patterns along the securement path 63
may replace three elastic members extending generally parallel to
the securement path.
Referring back to FIG. 3, the absorbent body 53 is somewhat
rectangular and is desirably constructed to be generally
compressible, pliable, non-irritating to the wearer's skin and
capable of absorbing and retaining liquid body waste, such as
urine. The absorbent body 53 overlays the inner layer 57 of the
outer cover 49, extending laterally between the leg elastic members
61, and is secured to the inner layer, such as by being bonded
thereto with adhesive 65.
The bodyside liner 51 overlays the absorbent body 53 to isolate the
wearer's skin from liquid body waste retained by the absorbent body
and is secured to at least a portion of the absorbent body, such as
by being bonded thereto with adhesive 87. The liner 51 further
extends beyond the absorbent body 53 to overlay a portion of the
inner layer 57 of the outer cover 49, particularly in the crotch
region 27 of the pants 21, and is secured thereto, such as by being
bonded thereto by adhesive 65, to substantially enclose the
absorbent body between the outer cover and the liner about the
periphery of the absorbent body. Although the bodyside liner 51
shown in FIG. 3 is slightly narrower than the outer cover 49, it is
understood that the liner and outer cover may be of the same
dimensions, or the liner may be sized larger than the outer cover,
without departing from the scope of this invention. It is also
contemplated that the liner 51 may not extend beyond the absorbent
body 53 and may not be secured to the outer cover 49 and/or to the
absorbent body 53. The bodyside liner 51 is desirably compliant,
soft feeling, and non-irritating to the wearer's skin and can be
less hydrophilic than the absorbent body 53 to provide a relatively
dry surface to the wearer and permit liquid body waste to readily
penetrate through its thickness.
The bodyside liner 51 can be manufactured from a wide selection of
web materials, such as synthetic fibers (e.g., polyester or
polypropylene fibers), natural fibers (e.g., wood or cotton
fibers), a combination of natural and synthetic fibers, porous
foams, reticulated foams, apertured plastic films, or the like.
Various woven and non-woven fabrics can be used for the bodyside
liner 51. For example, the liner 51 can be composed of a meltblown
or spunbonded web of polyolefin fibers. Alternatively, the liner 51
can be a bonded-carded web composed of natural and/or synthetic
fibers. The bodyside liner 51 can also be composed of a
substantially hydrophobic material, and the hydrophobic material
can, optionally, be treated with a surfactant or otherwise
processed to impart a desired level of wetability and
hydrophilicity. For example, the material can be surface treated
with about 0.45 weight percent of a surfactant mixture including
AHCOVEL.RTM. N-62 available from Uniqema, Inc., a division of ICI
of New Castle, Del., U.S.A, and GLUCOPON.RTM. 220UP available from
Cognis Corporation of Ambler, Pa., U.S.A, in an active ratio of
3:1. The surfactant can be applied by any conventional means, such
as spraying, printing, brush coating or the like. The surfactant
can be applied to the entire liner 51 or it can be selectively
applied to particular sections of the liner.
A particularly suitable bodyside liner 51 is constructed of a
non-woven bicomponent web having a basis weight of about 27 gsm.
The non-woven bicomponent can be a spunbonded bicomponent web, or a
bonded-carded bicomponent web. Suitable bicomponent staple fibers
include a polyethylene/polypropylene bicomponent fiber available
from CHISSO Corporation, Osaka, Japan. In this particular
bicomponent fiber, the polypropylene forms the core and the
polyethylene forms the sheath of the fiber. Fibers having other
orientations, such as multi-lobe, side-by-side, end-to-end may be
used without departing from the scope of the invention. Also,
although the outer cover 49 and bodyside liner 51 of the central
absorbent assembly 23 can include elastomeric materials, it is
contemplated that the central absorbent assembly may instead be
generally inelastic, wherein the outer cover, the bodyside liner
and the absorbent body 53 are composed of materials which are
generally non-elastomeric.
The front and rear side panels 37, 39 of the training pants 21 may
be bonded to the central absorbent assembly 23 at the respective
anterior and posterior regions 25, 29 of the pants and extend
outward beyond the laterally opposite edges 31 of the assembly. For
example, the front side panels 37 of the illustrated embodiment are
secured to the inner layer 57 of the outer cover 49, such as by
being bonded thereto by adhesive (not shown), by thermal bonding or
by ultrasonic bonding. These side panels 37 may also be secured to
the outer layer 55 of the outer cover 49, such as by being bonded
thereto by adhesive (not shown), by thermal bonding or by
ultrasonic bonding. The rear side panels 39 are secured to the
outer and inner layers 55, 57 of the outer cover 49, at the
posterior region 29 of the training pants 21, in substantially the
same manner as the front side panels 37. Alternatively, the side
panels 37, 39 may be formed integrally with the central absorbent
assembly 23, such as by being formed integrally with the outer
cover 49, the bodyside liner 51 or other layers of the pants
21.
Containment flaps, generally indicated at 91, are secured to the
bodyside liner 51 in generally parallel, spaced relation with each
other laterally inward of the leg openings 47 to provide a barrier
against the flow of urine to the leg openings. The containment
flaps 91 extend longitudinally from the anterior region 25 of the
training pants 21, through the crotch region 27 to the posterior
region 29 of the pants. Each containment flap 91 comprises a
non-woven layer 93 and a film layer 95 secured to the non-woven
layer, such as by being bonded thereto by adhesive 97. Flap elastic
members 99 are secured by suitable adhesive 101 between the
non-woven layer 93 and the film layer 95 generally at a distal end
103 of the flap 91, with the non-woven layer 93 being folded over
the flap elastic members 99 and the film layer 95 at the distal end
103. The flap 91 is secured to the bodyside liner 51 by a seam of
adhesive 107 to define a proximal end 109 of the flap.
The flap elastic members 99 of the illustrated embodiment comprise
three individual strands of elastomeric material extending
longitudinally along the distal end 103 of the flap 91 in generally
parallel, spaced relation with each other. One suitable elastic
strand is a LYCRA.RTM. T151 940 decitex elastic which can be
obtained from E.I. du Pont de Nemours Co. of Wilmington, Del. The
elastic strands are secured between the non-woven layer 93 and the
film layer 95 while in an elastically contractible condition such
that contraction of the strands gathers and shortens the distal end
103 of the containment flap 91. As a result, the elastic strands
bias the distal end 103 of each flap 91 toward a position spaced
from the proximal end 109 of the flap so that the flap extends away
from the liner 51 in a generally upright orientation of the flap,
especially in the crotch region 27 of the training pants 21, when
the pants are fitted on the wearer. It is understood, however, that
the containment flaps 91 may be omitted from the training pants 21
without departing from the scope of the invention.
While the elastic composite constructed in accordance with the
present invention is shown and described above with particular
reference to children's toilet training pants 21, and more
specifically to the leg openings 47 of children's toilet training
pants, it is understood that the elastic composite as referred to
herein comprises any composite in which an elongate elastic member
is applied to a flexible substrate, or between two such substrates,
to provide retractive or stretching forces to the substrate in
accordance with the present invention.
The substrate may be a film, woven fabric, knit fabric or non-woven
fabric. Such fabrics may be of natural or synthetic fibers such as
cotton, wool, polyester, nylon, polypropylene, polyethylene, or the
like. The film may be of polyethylene, polyester,
polyflourocarbons, polyimide, polypropylene, or the like. For
example, the flap elastic members 99 of the training pants 21 of
FIGS. 1-3 may be secured between the non-woven layer 93 and the
film layer 95 of the flaps 91 in accordance with the elastic member
patterns shown and described herein. Elastic members may also be
secured to the training pants 21 at the front and rear waist edges
33, 35 thereof in accordance with the elastic member patterns shown
and described herein.
The substrate may also be a generally continuous web, such as for
forming multiple individual garments such as training pants whereby
the web is cut into individual garments after the elastic members
are secured to the web. In such an embodiment, the securement path
63 defines a pattern that is repeated once for each individual
garment to be cut from the web.
It is contemplated that the elastic composite of the present
invention may be formed or incorporated in various other garments.
For example, other disposable absorbent articles, such as diapers
and other infant and child care products, adult incontinence
garments and other adult care products, sanitary napkins and other
feminine care products and the like, as well as surgical bandages
and sponges, may have one or more elastic members secured to one or
more layers thereof in accordance with the present invention.
Conventional garments such as pants, socks, shirts, hats, coats and
the like may also have one or more elastic members secure to one or
more layers thereof in accordance with the present invention.
Alternatively, an elastic composite may be formed separately from a
garment, such as in the form of an elastic strip or ribbon, and
subsequently secured to a garment to provide an elastic component
to the garment without departing from the scope of this
invention.
FIGS. 6-11 illustrate an apparatus, generally indicated at 201, of
the present invention for guiding one or more elastic members 61
(FIGS. 1-5) onto a substrate moving in a flow direction, indicated
by the direction arrow F in the various figures, for securement to
the substrate to form an elastic composite such as the training
pants 21 of FIGS. 1-5. The apparatus 201 comprises a guide
assembly, generally indicated at 203, which receives and guides one
or more elastic members 61 onto the substrate, and a drive
assembly, generally indicated at 205, which controls the position
and operation of the guide assembly relative to the flow direction
of the substrate. The drive assembly 205 comprises a base 207
secured against lateral movement relative to the flow direction of
the substrate, and is desirably further secured against movement
generally in the flow direction of the substrate. The base 207 of
the illustrated embodiment is a generally rectangular plate
constructed of plastic. However, the base 207 may have other
configurations, such as a table, a box-shaped housing or other
suitable configuration, and may be constructed of a material other
than plastic, such as metal or wood.
Two gears 209a, 209b are rotatably mounted on the base 207 by
respective fasteners 213 for rotation relative to the base about
respective rotation axes of the gear fasteners. The gears 209a,
209b are interengaged so that rotation of one gear, e.g.,
clockwise, drives the other gear to rotate in a counter direction,
e.g., counter-clockwise. As shown in FIG. 6, one gear 209a is
desirably operatively connected, such as via a drive gear (not
shown) or drive pulley (not shown) to a drive mechanism 210 (e.g.,
a motor) capable of driving rotation of the gear. The drive
mechanism 210 is desirably controllable, such as by a suitable
control system 212 to facilitate powered, controlled rotation
(e.g., clockwise and/or counter-clockwise rotation) of the gears
209a, 209b relative to the base 207 in accordance with a
pre-determined pattern to be formed by the elastic member(s) 61
guided onto the substrate. It is contemplated that the gears 209a,
209b may be out of engagement with each other, so that they may be
rotated independently of each other either by a common drive
mechanism or by separate drive mechanisms. It also contemplated
that the drive assembly 205 may have only one gear or that the
gears 209a, 209b may be omitted altogether without departing from
the scope of this invention.
Pulleys 211 are seated on the gears 209a, 209b in coaxial relation
therewith and secured by the respective gear fasteners 213 in
engagement with the gears for conjoint rotation therewith about the
respective rotation axes of the fasteners. Linkage comprising two
linkage bars 215 is pivotally connected at one end 217 to the base
207 in parallel, spaced relation with each other for pivoting an
opposite end 219 of the linkage bars 215 relative to the base to
move the opposite end of the linkage bars generally laterally
relative to the flow direction F of the substrate. The guide
assembly 203 comprises a guide plate 225 pivotally connected to the
opposite end 219 of the linkage bars 215 to permit lateral movement
(e.g., as shown in FIG. 11) of the guide plate 225 relative to the
base 207 and the flow direction F of the substrate while the
angular orientation of the guide plate relative to the flow
direction of the substrate remains generally constant. The guide
plate 225 may be manually moved relative to the base 207 or, more
desirably, it may be operatively connected to a drive mechanism
(not shown) and corresponding control system (not shown) to permit
powered, controlled movement of the guide plate relative to the
base and the flow direction F of the substrate. It is contemplated
that the linkage may instead comprise a single linkage bar
pivotally connected at one end to the drive assembly and at its
opposite end to the guide assembly 203 without departing from the
scope of this invention.
The guide plate 225 of the illustrated embodiment is generally
rectangular and is constructed of plastic. However, the guide plate
225 may have other configurations and it may be constructed of a
material other than plastic, such as wood or metal, without
departing from the scope of this invention. It is contemplated that
the guide plate 225 may have an angular orientation relative to the
flow direction F of the substrate other than the orientation shown
in FIGS. 6-11, such as by being angled relative thereto. It is also
contemplated that the guide plate 225 may not be connected to the
base 207, or more generally to the drive assembly 203 so that the
guide assembly may be moved relative to the flow direction of the
substrate independent of the drive assembly, and that the guide
assembly may instead be adapted for sliding movement transverse to
the flow direction F of the substrate, without departing from the
scope of this invention.
With particular reference to FIG. 6, the guide assembly 205 further
comprises a pair of pulleys 227 corresponding to the drive assembly
pulleys 211 mounted on the base 207. The pulleys 227 are rotatably
mounted on the guide plate 225 by fasteners 229 for rotation
relative to guide plate about the corresponding rotation axes of
the fasteners. A spacer 231 (FIGS. 7 and 8) is secured by each
fastener 229 between each guide assembly pulley 227 and the guide
plate 225 to position the guide assembly pulleys above the guide
plate at a level corresponding to the level of the drive assembly
pulleys 211. The spacer 231 is desirably a bushing or a set of
bearings, although other structure may be used as the spacer and
remain within the scope of this invention. Continuous belts 235,
having respective inner and outer reaches, respectively indicated
at 237 and 239, are supported in tension by the corresponding guide
assembly pulleys 227 and drive assembly pulleys 211 whereby
rotation of the drive assembly pulleys rotates the guide assembly
pulleys relative to the guide plate 225 in the same direction of
rotation as the drive assembly pulleys. Desirably, the pulleys 211,
227 and belts 235 include interengaging teeth to inhibit slippage
of the belts on the pulleys.
Where the drive assembly gears 209a, 209b are interengaged as in
FIG. 1 for counter-rotation relative to each other, the guide
assembly pulleys 227 rotate in counter directions upon rotation of
the drive assembly gears. The lateral spacing between the guide
assembly pulleys 227 is substantially the same as the lateral
spacing between the drive assembly pulleys 211, and all of the
pulleys are of the same size, so that the drive ratio of each drive
assembly pulley to its corresponding guide assembly pulley is
generally one to one. However, it is contemplated that the guide
assembly pulleys 227 may instead be larger or smaller than the
drive assembly pulleys 211 to obtain different drive ratios. It is
also contemplated that the spacing between the guide assembly
pulleys 227 may be greater or lesser than the spacing between the
drive assembly pulleys without departing from the scope of this
invention.
Each guide assembly pulley 227 has a positioning arm 241 mounted
thereon generally at an inner end 243 of the positioning arm. The
positioning arm 241 is held by the fastener 229 in engagement with
the pulley 227 so that rotation of the pulley conjointly pivots the
positioning arm about the rotation axis of the fastener. The
positioning arm 241 extends radially out from the inner end 243 to
an outer end 245 thereof which moves generally laterally relative
to the flow direction F of the substrate as the positioning arm
pivots about the rotation axis of the fastener 229. Inner (or
first) and outer (or second) pulleys, indicated respectively at 247
and 249, are mounted on each positioning arm 241, with the inner
pulley being located near the inner end of the positioning arm in
coaxial relationship with the rotation axis of the fastener 229 and
secured against rotation with respect to the arm about the fastener
rotation axis. The outer pulley 249 is mounted on the positioning
arm 241 in radially spaced relation with the inner pulley 247, such
as near the outer end 245 of the positioning arm, for conjoint
orbital movement with the outer end of the positioning arm relative
to the guide plate 225 and the substrate about the rotation axis of
the fastener 229 (and hence about the fixed, inner pulley). The
outer pulley 249 is rotatable relative to the positioning arm 241
about a rotation axis of the outer pulley. A continuous belt 251 is
supported in tension by the inner and outer pulleys 247, 249 so
that orbital movement of the outer pulley about the fixed, inner
pulley causes the outer pulley to rotate about its rotation axis
relative to the positioning arm 241.
The outer pulley 249 has a guide 253 mounted thereon for receiving
and guiding one or more elastic members 61 onto the substrate as
the substrate is moved in its flow direction F. The guide 253 is
mounted on the outer pulley 249 generally radially offset from the
rotation axis thereof for orbital motion about the rotation axis of
the outer pulley upon rotation of the pulley. Each guide 253 is
mounted on the respective outer pulley 249 in a desired angular
orientation relative to the flow direction F of the substrate,
e.g., transverse thereto in the illustrated embodiment. The guides
253 shown in FIGS. 6-11 each comprise a rectangular block
constructed of a transparent plastic material and mounted on the
outer pulley 249 by a post 255 extending up from the pulley. A
suitable fastener 257 extends laterally through each block to
secure each block to the respective post 255 at an angular
orientation relative to the flow direction F of the substrate. It
is understood that the guide 253 may be constructed other than of
plastic and may have a shape other than rectangular without
departing from the scope of this invention. It is also contemplated
that the guide 253 may be secured to the outer pulley 249 other
than by a post 255 and/or fastener 257, such as by being
permanently secured thereto, and remain within the scope of this
invention.
The guides 253 each have a set of slots 259 formed therein. Each
slot is sized for receiving one elastic member and guiding it onto
the substrate. Instead of slots 259, the guides may have holes (not
shown) formed therethrough without departing from the scope of this
invention. It is also contemplated that instead of a block, the
guides 253 may be in the form of an eyelet or other suitable form
for receiving and guiding one or more elastic members 61 onto the
substrate. While the guides 253 of the illustrated embodiment each
have four slots 259 formed therein, the guides may have any number
of slots, including one slot, depending on the number of elastic
members 61 to be guided onto the substrate.
Also, while not shown in the drawings, the guides 253 may be
mounted to the outer pulleys 243 at different heights relative to
each other, such as by providing posts 255 of different lengths, or
by using the fastener 257 to adjust the relative heights of the
guides on the posts. Positioning the guides 253 at different
heights above the outer pulleys 249 provides sufficient clearance
for using longer guides that generally cross above or below one
another as they move transverse to the flow direction F of the
substrate upon pivoting movement of the positioning arms 241 and
corresponding rotation of the outer pulleys. In this manner,
elastic members 61 guided onto the substrate by the guides 253 can
cross each other within the securement path 63 of the elastic
members as shown in FIG. 2.
It is also contemplated that the positioning arms 241 may be
disposed at different heights relative to each other above the
guide plate 225, or one positioning arm may be positioned above the
guide plate and the other may be positioned below the guide plate,
to provide sufficient clearance for the positioning arms to pivot
up to 360.degree. about the rotation axes of the fasteners 229. The
outer pulleys 249 supporting the guides 253, and hence the guides
themselves, are orbital relative to the substrate about the
rotation axes of the fasteners through a generally circular path.
In this manner, the drive mechanism may continuously rotate the
drive assembly pulleys 209a, 209b through a full rotation to vary
the transverse positions of the guides 253 relative to the flow
direction F of the substrate, instead of oscillating the rotation
of the pulleys back and forth through smaller rotations. The
positioning arms 241 may also be of different lengths so that
elastic the patterns formed by the elastic members 61 guided onto
the substrate by the guides 253 have different amplitudes A.
In operation of the apparatus 201 to guide an elastic member 61
onto a substrate moving in a flow direction F of the substrate
(e.g., so as to form the periodic pattern of the elastic member on
the substrate), the guide plate 225 is initially positioned at a
desired transverse position relative to the base 207, such as in
longitudinal relation therewith so that the linkage bars extend
generally in the flow direction of the substrate as shown in FIGS.
6 and 7. The positioning arms 241 are also positioned at a desired
angular position relative to the guide plate 225 and the flow
direction F of the substrate, such as outward from the guide plate
generally in the flow direction of the substrate as is also shown
in FIGS. 6 and 7. It is understood, however, that the initial
positions of the guide plate 225 and positioning arms 241 may be
other than that shown in FIGS. 6 and 7 without departing from the
scope of this invention. One or more elastic members 61 (FIGS. 2,
4A, 4B and 5) are received in the slots 259 of each guide 253 and
directed therefrom onto the substrate for adherence to the
substrate.
To vary the transverse position of the elastic members 61 relative
to the flow direction F of the substrate while the securement path
63 remains generally parallel to the flow direction F of the
substrate, one of the drive assembly gears, e.g., gear 209a (and
hence the pulley 211 seated thereon) is rotated relative to the
base 207, such as by the drive mechanism, in a desired direction of
rotation, such as clockwise. The other gear 209b and pulley 211 are
correspondingly rotated in a counter-clockwise direction. The guide
assembly pulleys 227 are accordingly driven, via the continuous
belts 251, in counter-rotating directions to pivot the positioning
arms 241 about the respective rotation axes of the fasteners 229 in
counter directions. For example, clockwise rotation of the drive
assembly gear 209a effects pivoting of the positioning arms 241 to
move generally out away from each other as shown in FIGS. 9 and
10.
Pivoting movement of the positioning arms 241 also effects orbital
movement of each outer pulley 249 about its corresponding fixed,
inner pulley 247 to effect lateral movement of the outer pulley and
the guide 253 mounted thereon relative to the flow direction F of
the substrate. As a result of the tension in the continuous belts
251 supported by the inner and outer pulleys 247, 249, the outer
pulleys are rotated about their respective axes relative to the
positioning arms 241. In turn, the guides 253 mounted on the outer
pulleys 249 orbit about the respective rotation axes thereof, such
as in a direction counter to the direction about which the
positioning arm 241 is pivoted, so that the angular orientation of
each guide relative to the flow direction F of the substrate
remains substantially constant as the guides are moved laterally
relative to the flow direction of the substrate. As shown in FIG.
11, to vary the securement path 63 laterally relative to the flow
direction F of the substrate, the guide plate 225 is moved
laterally relative to the base 207, and hence laterally relative to
the flow direction of the substrate.
FIGS. 12 and 13 illustrate a system, generally indicated at 301, of
the present invention for applying one or more elongate members,
such as elastic members 61 or inelastic members (not shown) to a
substrate to form a composite, and more particularly for applying
elastic members to disposable absorbent articles such as diapers or
the training pants 21 of FIGS. 1-3 to form the elastic leg openings
47 thereof. The system 301 generally comprises a conveyance
mechanism (not shown), such as a vacuum conveyor, for conveying a
first substrate 303 (e.g., the inner layer 57 of the outer cover 49
of the training pants 21) from a source (not shown) of substrate
material to pass over an idler roller 305 and then through a nip
307 defined by a pair of rollers 309 in a flow direction of the
substrate material. A second conveyance mechanism (not shown), such
as another vacuum conveyor, conveys a second substrate 311 (e.g.,
the outer layer 55 of the outer cover 49 of the training pants 21)
to pass over another idler roller 313 and through the nip 307 in
opposed relation with the first substrate 303. Adhesive (not shown)
is desirably applied to the first substrate 303 and/or the second
substrate 311, such as by spraying adhesive thereon, upstream from
the nip 307. It is contemplated that as an alternative, or in
addition to applying adhesive to one or both of the substrates 303,
311, adhesive may be applied to the elastic members 61 before the
elastic members are adhered to the substrates or the elastic
members may be self-adhering.
A pair of apparatus 201 of the present invention, e.g., for
applying a pair of elastic members 61 to the pants 21 generally
adjacent a respective one of the leg openings 47 of the pants, are
positioned upstream of the nip 307 for guiding the elastic members
onto the substrates 303, 311 before the substrates pass through the
nip. The apparatus 201 are spaced laterally from each other (FIG.
13) and vertically from each other (FIG. 12) to provide sufficient
clearance for pivoting movement of the positioning arms 241 of the
apparatus. As best seen in FIG. 12, one apparatus 201 is inverted
relative to the other apparatus. However, the apparatus 201 may
both be upright, or they may both be inverted, and they may be at
the same height or different heights, without departing from the
scope of this invention. Elastic members 61, such as elastic
strands, are pulled off of one or more unwinds (not shown) and
around idler rollers 315 before being fed through the guides 253
(e.g., with one elastic member received in each guide) of each
apparatus 201 for guiding the elastic members onto the substrates
303, 311 for adherence therebetween so that the substrates and
elastic members together pass through the nip 309.
The apparatus 201 are each operated as described above to guide the
elastic members 61 onto the substrates 303, 311 along a desired
securement path 63, and in a desired pattern within the securement
path. For example, the guide plates 225 of each apparatus 201 are
moved laterally relative to the flow direction F of the substrates
303, 311 to vary the securement paths 63 of the elastic members 61
laterally relative to the flow direction F of the substrates
generally in accordance with the contour of the side edges 31 of
the training pants 21. The control system 212 is operated to move
the guides 253 of each apparatus 201 laterally relative to the flow
direction F of the substrates 303, 311 to alter the transverse
position of the elastic member within the securement path 63.
For example, to guide the elastic members 61 onto the substrates
303, 311 in a generally periodic pattern along the securement path
63, the control system operates the drive mechanism to oscillate
one drive assembly gear 209a of each apparatus 201 through
clockwise and counter-clockwise rotations corresponding to the
desired shape and period of the pattern. In accordance with
operation of the apparatus 201 as described previously, the guides
253 of each apparatus are thus oscillated through movements
laterally relative to the flow direction F of the substrates 303,
311, and more particularly transverse to the securement path 63, to
guide the elastic members 61 onto the substrates in accordance with
the desired pattern. As the elastic members 61 are guided onto the
substrates 301, 311, the elastic members are adhered between the
substrates. Subsequently passing the substrates 303, 311 and
elastic members 61 through the nip 307 serves to further secure the
elastic members between the substrates and can further serve to
secure the substrates together. However, the step of passing the
substrates through the nip may be omitted without departing from
the scope of this invention.
The amplitude of the periodic wave pattern defined by each elastic
member 61 is generally a function of the radial spacing of the
outer pulley 249 from the inner pulley 247 on the positioning arm
241 and the angle through which the positioning arm is pivoted. The
period of the periodic wave pattern is generally a function of the
rate at which the substrates 303, 311 are fed in the flow direction
thereof to the nip 307 and the rate at which the positioning arm
241 is pivoted relative to the flow direction of the substrate. The
slope S (FIG. 4A) defined by the elastic member 61 as it extends
transversely within the width W of the securement path 63 thereof
is determined by controlling one or more of the rate at which the
substrates are fed through the nip 307, the transverse positioning
of the guide relative to the flow direction F of the substrates and
the rate at which the guide is moved relative to the flow direction
of the substrates.
When introducing elements of the present invention or the preferred
embodiment(s) thereof, the articles "a", "an", "the" and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising", "including" and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
As various changes could be made in the above constructions without
departing from the scope of the invention, it is intended that all
matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
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